Philipsen, Tine E. MD*; Hendriks, Jeroen M. MD, PhD*; Lauwers, Patrick MD*; Voormolen, Maurits MD†; d’Archambeau, Olivier MD†; Schwagten, Veerle MD‡; Fias, Lore MD*; Van Schil, Paul E. MD, PhD*
Patients with ruptured abdominal aortic aneurysm (rAAA) have a high overall mortality rate up to 85% to 90%.1,2 Fast diagnosis and decision making are important for final outcome. If a patient with a history and physical examination suggestive for AAA presents at an emergency department (ED), close monitoring is necessary and an abdominal ultrasound needs to be performed without any delay. If ultrasound findings confirm the presence of a rAAA in a hemodynamic unstable patient, urgent treatment is required. In case of instability, patients are usually treated by performing an emergency laparotomy with direct cross-clamping of the abdominal aorta at the infrarenal or juxtarenal level. Perioperative mortality for this group, however, remains high (32%–80%) and has not improved significantly over the last two decades.1,3–5
During the past years, endovascular repair (EVAR) has become a treatment option for rupturing AAA in stable patients, in an effort to improve survival. Since then, perioperative morbidity and mortality in stable patients have improved for EVAR compared with open surgery, though mortality rates are still up to 21%.1 For unstable patients the indication for EVAR is still under discussion.4–6 By temporarily stabilizing the patient by means of endovascular balloon occlusion of the juxtarenal aorta, the time interval for treatment decision is prolonged and unstable patients with rAAA become candidates for an endovascular approach again.7,8 When angiogram shows unsuitable anatomy for EVAR, open repair is performed immediately but made easier, and better visualization of the aneurysm and periaortic structures is realized.3,8
PATIENTS AND METHODS
Between January 2006 and July 2008, all patients that were referred to our ED with a history and physical examination suggestive for rAAA and signs of hemodynamic instability entered the rapid endovascular balloon occlusion (REBO) protocol (Fig. 1). Instability was defined as severe hypotension with a systolic blood pressure less than 60 mm Hg, history of prehospital syncope or unconsciousness at presentation, electrocardiogram signs of cardiac ischemia and/or need for intubation. Parameters on admittance were reviewed. The Hardman index9 was calculated for all patients, but no exclusion for treatment was made based on this result. An urgent ultrasound examination was performed at the ED, to confirm the presence of a rAAA.
REBO protocol: once defined unstable and with diagnosed rAAA, patients are transferred immediately to the operating room (OR). The patient is installed in supine position on a radiolucent operating table (Alphamaquet 1150.16, MAQUET, Rastatt, Germany). While the anesthesiologist places a central jugular access and an arterial radial line in the awake patient (unless intubation is required), groins are locally anesthetized with marcaine 0.5% by the vascular surgeon and the common femoral artery (CFA) on one side is accessed.
Initially a Seldinger’s technique is attempted but in case of failure after two attempts, an arterial femoral cut down with local anesthesia is performed and the CFA is punctured under direct vision. No heparin is administered before a decision regarding the operation technique is made. Once the CFA is punctured, a 0.035 in. heavy-duty guidewire (Terumo, Belgium) is introduced with fluoroscopic control (OEC 9800 mobile fluoroscopic unit, GE OEC Medical systems) and exchanged for a 4-Fr pigtail catheter (65 cm length – Terumo, Belgium). A stiff 180-cm long Backup-Meier guidewire is introduced and a 12-Fr sheath (Medtronic, Brussels, Belgium) is placed in the CFA. Next, a Reliant aortic balloon (Medtronic) is introduced over the Backup-Meier and inflated at the level of the renal arteries (the level of the 12th dorsal—1st lumbar vertebra) or more proximally in case a juxtarenal rAAA was suspected on ultrasound examination at the ED. The Backup-Meier is left in place for stabilizing the Reliant balloon in the aorta and prevents this balloon from dislocating downstream. The Reliant balloon has a usable length of 100 cm and an inflation diameter ranging from 10 to 46 mm (Figs. 2, 3). Once the balloon is installed, general anesthesia is induced, the patient is intubated and blood pressure is stabilized with a maximum of 100 mm Hg systolic (permissive hypotension). Through the balloon lumen, an angiogram is performed to confirm balloon position and to localize the renal arteries. A manual injection of 10 mL conventional iodinated contrast fluid is sufficient. By puncturing the contralateral CFA using Seldinger’s technique, a second pigtail catheter is now introduced and an extensive aortogram is performed through the pigtail catheter with the occlusion balloon inflated in place, to decide whether or not the patient is a candidate for EVAR. The pigtail catheter is calibrated, for measurement of the aortic dimensions to determine the size of the endoprosthesis.
In case of favorable anatomy, patient is treated endovascularly by means of an aorto-uni-iliac endoprosthesis (AUI – Talent, Medtronic), which is available in the operating theater. The endograft is inserted through the contralateral CFA after exchanging the pigtail catheter for a second stiff Backup-Meier guidewire. The Reliant aortic balloon is deflated on expansion of the endoprosthesis. After expansion of the endograft, an aortogram is performed to confirm the position and to exclude endoleak. Subsequently, an endovascular occluder (Medtronic) is placed in the contralateral common iliac artery (CIA) and a femorofemoral crossover bypass (Silver Dacron graft, 8 mm, Intervascular, Brussels, Belgium) is performed (Figs. 4, 5).
If endovascular treatment is no option because of limited visualization, too short length of the neck of the aneurysm or tortuosity, stenosis or aneurysmatic dilatation of the iliac arteries, we choose for open repair and replacement by means of a tube or bifurcated aortic graft (Silver Dacron graft, Intervascular or Albograft, LeMaitre vascular, Sulzbach, Germany). The endoaortic Reliant balloon is left inflated until proximal and distal clamps can be applied. Once arteries are clamped, heparin is given with a minimal activated clotting time above 300 seconds.
Statistical analysis on this series was not performed because of the limited number of patients presented. Because of the retrospective nature of the study, no comparison was made with other techniques.
A total of 12 patients were stabilized by means of percutaneous transfemoral endovascular balloon occlusion of the juxtarenal aorta during the study period. Patient demographics are shown in Table 1.
All patients were men with a mean age of 71 years (range 59–87 years). Diagnosis was based on ultrasound examination at the ED in four patients. In six patients, transferred from other centers, an angio computed tomography (CT) scan of the abdomen confirmed a ruptured infrarenal abdominal aneurysm. Soon after their CT scan was performed, patients, however, became instable and were transferred immediately to our hospital. In two additional patients, the AAA was an incidental finding on an abdominal CT scan because of acute abdominal pain. The mean diameter of the ruptured AAA was 87 mm (range 58–110 mm) (Table 2). The delay time between admittance at our ED and start of treatment at the OR by means of REBO was less than 60 minutes for all cases. For all patients, the REBO procedure was performed within 10 minutes after arrival in the OR. Inflation of the aortic balloon at the level of the juxtarenal aorta lead to hemodynamic stability with rapid recovery of the systolic blood pressure. On aortogram after stabilization, only seven of the 12 patients were found candidates for endovascular exclusion of the rAAA, based on current morphologic criteria (Table 2).
In five of the seven EVAR candidates (71%), the procedure was successfully performed, although one patient needed iliac extensions because of an aneurismal CIA. On dilatation of the iliac extension, free rupture of the calcified CIA was seen so open iliac repair was performed.
In the other two patients who were anatomically suitable for endovascular exclusion, EVAR was technically impossible and conversion to an open repair was subsequently performed. In the first converted patient, a bilateral stenosis of a tortuous CIA inhibited introduction of the endograft. A 10 × 38 mm balloon expandable stent was placed at the site of the iliac stenosis to expand the entry for the endoprosthesis, but insertion of the endograft remained impossible. Conversion and open dissection with protection by the endovascular balloon and subsequent placement of an aortobifemoral graft was performed successfully. In the second patient, the AUI endoprosthesis was placed well but during placement of the occluder in an aneurysmatic right CIA (3.6 × 3.2 cm), the patient developed hemodynamic instability. The aortic balloon was inflated again at the juxtarenal level to stabilize the patient. Angiogram showed a type 1c endoleak (occluder endoleak)10 and open ligation of the CIA was performed. Despite construction of a correct femorofemoral crossover bypass, the leg at the side of the occluder remained ischemic because of an inflow problem, which could not be visualized with repeat angiogram. We decided to convert to an open aortobifemoral repair with intention to improve inflow to the both legs.
In the patients who were not candidate for EVAR, open aortic replacement by a classic aortobi-iliacal or aortobifemoral graft was performed. All patients but one survived the operative procedure and were monitored postoperatively on the intensive care unit (ICU). Mean postoperative stay on the ICU was 8.4 days (range 2–24 days) for the EVAR group and 19.67 for the open group (range 12–28 days). The mean hospital stay for survivors was 24 days (range 5–75 days) for the EVAR group, compared with 45 days for the open group (range 28–86 days).
For the patients that were treated with an endoprosthesis (EVAR group; n = 5), no in-hospital mortality was recorded. The postoperative course was uneventful. The mean hospital stay for the five EVAR patients was high because of the prolonged stay of one patient, who developed bilateral pneumonia and needed prolonged ICU stay. For the four other EVAR patients, the mean hospital stay was only 11 days. All the patients treated by EVAR were discharged home without further revalidation. So far, no secondary procedures were required. Mean follow-up time is currently 8.4 months (range 1–15 months).
In the group of patients treated by open repair (open group; n = 5), one patient did not survive the procedure. This patient was an 87-year-old man who presented with severe hypovolemic shock. Ultrasound showed an AAA with presence of free intra-abdominal fluid. On placement of the aortic balloon, patient was hemodynamically stabilized with a blood pressure of about 80/50 mm Hg. Aortogram showed iliac kinking and stenosis, but also a total free rupture of the abdominal aorta. Transfusion was not possible because of religious reasons, and therapeutic abstinence followed in his decease. In two of the other four open-treated patients, postoperative course was complicated by transient renal failure that did not require hemodialysis. These four patients were discharged to revalidation facilities for further convalescence. Mean follow-up time is currently 11 months (range 9–17 months).
In the group that needed conversion to an open procedure (converted group; n = 2), one patient developed ischemia of the left hemicolon, which was successfully treated by means of a partial colectomy, and further recovery was uneventful. The second patient developed pulmonary failure, progressive ischemia of the right leg, renal failure requiring hemodialysis, and septic shock. He died on the 50th postoperative day because of ventricular fibrillation.
Our total experience of percutaneous transfemoral aortic balloon occlusion was presented as a feasible and successful technique to convert unstable patients with rAAA to hemodynamic stability. In all patients, the REBO procedure could be performed within 10 minutes after arrival at the OR. Recovery of hemodynamic parameters was seen immediately on balloon inflation.
As has been described, the CFA can mostly be punctured percutaneously, even in the hypotensive patient.7,8 We encountered no problems in accessing the CFA or installing the aortic balloon, in which fluoroscopy has proven to be an essential procedural step, to control for perforation and this way avoiding free aortic rupture.
In the hemodynamic unstable patient, induction of general anesthesia could provoke an even more life-threatening hypotension. By hemodynamic stabilization under local anesthesia before induction, the effect of the induction-related hypotension is considerably reduced.
The REBO procedure prolongs the decision interval for treatment. This way, patients become candidates for endovascular treatment again, possibly avoiding urgent laparotomy and open aortic cross-clamping. Therefore, hemodynamic instability should no longer been seen as a contraindication for endovascular AAA repair. The choice of treatment should be based on anatomic rather than hemodynamic criteria.2
Furthermore, no patients should be withheld from EVAR because resources are not available at the time of presentation, as previously described.1 Because of shelf stock limitations, all patients in our series that were suited for endovascular approach were treated by means of an aorto-uni-iliac endo-aortic prosthesis. AUI stent grafts are known to be associated with quicker decompression of the bleeding aneurysm and less anatomic restrictions.11 A bifurcated endograft can, however, also be placed without problems after the REBO procedure is performed, as has been stated in literature.4
Opposed to routine preoperative imaging protocols described in literature,4,5 preoperative CT scan was not obligatory in four of 12 patients to take decision whether treatment should be attempted endovascularly or by open route. In these four unstable patients, diagnosis was made by history, clinical examination, and ultrasound at the ED. The six patients who were transferred to our ED, however, did undergo a preoperative CT scan in the center of origin.
After stabilization by an endovascular aortic balloon, an aortogram was performed in all patients to decide whether or not patient was a candidate for EVAR. Opposed to previous reports,7 we had acceptable visualization of the aortic anatomy and tributaries by manual injection of conventional iodinated contrast. Based on the current (morphologic) criteria, seven of the 10 patients were suitable for endovascular exclusion of the rAAA. Of these seven patients, only five (71%) were eventually treated by means of EVAR, whereas two needed conversion to an open procedure because of access problems at the aneurysmatic/stenotic common iliac arteries. Therefore, when decision for endovascular treatment is made based on an aortogram, iliac anatomy should also be taken into account.
Preoperative CT scan in our group was not obligatory for decision to treat by means of EVAR in rAAA. In all patients treated by EVAR, the aortogram showed a sufficiently long neck (Table 2) without presence of thrombus. These morphologic features were confirmed by means of postoperative control CT scan, which showed comparable images and onset of the aneurysmal thrombus at the origin of the aneurysmal dilatation.
In case of unfavorable aneurismal anatomy, the REBO procedure can be used as a bridge to open repair in unstable patients. Dissection and aortic cross-clamping can be performed more cautiously in case of regained hemodynamic stability. Consequently, exclusion of treatment based on a Hardman index >2 as suggested in the literature9 should not be done. In our series, the two fatalities presented with a Hardman index of 2, whereas a patient with a Hardman index of 3 survived an open procedure without irreversible complications.
The indication for REBO may also be extended to patients with other (aortic) pathologies, such as aortic leakage (eg, due to aorto-enteric fistulae) and AAA in patients, in whom extensive blood loss is to be prevented. In this series, however, we did not compare the amount of blood loss in patients with rAAA stabilized by REBO and treated by means of open aortic repair to patients who were not stabilized by means of REBO before the intervention.
In the past, the proximal control of aortic aneurysms has been obtained by means of laparotomy or left thoracotomy with cross-clamping or direct occlusion by means of a Foley catheter.3 These techniques implied open aneurysm repair under general anesthesia. REBO in open aortic repair for rAAA has been used with successful control of hemodynamic stability before laparotomy.12 Recent literature,1,4 including a systematic review and meta analysis of studies in which endovascular treatment was used for repair of rAAAs, however, stated, that none of the authors of the 18 included observational studies recommended the routine use of an aortic exclusion balloon.1 In a study by Anain et al,4 the use of balloon occlusion was even correlated with a significantly higher mortality in the patients treated by EVAR. However, no criteria for the use of balloon occlusion were specified. In our group, 30-day mortality of unstable patients with rAAA treated by EVAR was 0%. The overall mortality for all patients unregarded their treatment (either open or EVAR) was 17% (two of 12 patients), which seems to be lower than mortality in most studies of unstable patients with rAAA, treated without REBO. Therefore, we use an endovascular aortic occlusion balloon in all patients with rAAA, especially in hemodynamically unstable patients. However, we acknowledge that larger study groups are needed for further evaluation of the efficacy of REBO in unstable patients.
In conclusion, we state that REBO of the juxtarenal abdominal aorta by percutaneous technique in unstable patients with rAAA resulted in a 83% 30-day survival, and an event-free survival after discharge from the hospital of 100%. With this technique, EVAR exclusion is still a valuable treatment option while exposure and decision making in the open group is easier to perform with less risk for additional damaging to neighboring structures during dissection of the aorta because urgent cross-clamping of the rAAA is not necessary. Therefore, we use transfemoral balloon occlusion of the juxtarenal aorta in all unstable patients with ruptured AAA.
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This manuscript represents an emerging understanding of the important and essential role in which endovascular technologies can impact the treatment of cardiovascular diseases. Philipsen, et al, have implemented a new treatment paradigm for the management of critically ill patients with ruptured abdominal aortic aneurysms. The most important paradigm shift described in this manuscript is that the aorta can be quickly and safely occluded in an emergent situation using an occlusive balloon introduced through a percutaneous approach–thus minimizing hemodynamic instability and allowing the anesthesiologist to induce the patient without hypotension. It is left to larger studies to determine if this is truly a benefit to patient outcomes, but this manuscript and others suggest this may be the case. In addition, rapid aortic occlusion does not alter the intended method of treatment for these patients. Patients can still be treated using an open or endovascular approach. Clearly, this is another example in which new technology can potentially transform our approach to complex cardiovascular diseases.
© 2009 Lippincott Williams & Wilkins, Inc.